In mobile communications between a base station (BS) and a user equipment (UE), diversity receivers are used in the user equipment to improve the reception of radio signals sent by the base station. The diversity receivers improve the quality of the received signal. The use of receive diversity, however, leads to significantly increased power consumption, considerably reducing the available talk times. Therefore, there is a need to provide a user equipment that efficiently uses battery power to provide high talk times at high signal quality.
In 3GPP (3rd Generation Partnership Project) standardization, performance requirements are specified for reception of the DPCH (dedicated physical channel) fulfilling the so called “Enhanced Performance Requirements Type 1”. These Type 1 requirements refer to user equipments using receive diversity (RxDiv, two or more receive antennas) according to 3GPP Technical Specification TS 25.101 V7.16.0 (2009-05), Section 8.3, 8.6, 8.8. In order to fulfill these requirements it is necessary according to 3GPP to operate the RxDiv receiver all the time in RxDiv mode, i.e. with both antennas being activated and with the full receive diversity receiver being activated. The frequency of occurrence of call drops which is one of the major quality criteria used for finally deployed devices used by network (NW) operators and handset vendors will be significantly reduced when RxDiv is used because RxDiv provides a considerable SNR gain, e.g. 3 dB minimum without fading and without antenna correlation and even larger gains with fading and without antenna correlation. On the other hand, the usage of RxDiv, however, leads to significantly increased current consumption, reducing the talk time considerably.
For these and other reasons there is a need for the present invention.